Colored diamonds are a superconductor’s best friend

Nitrogen-vacancy centers — flaws in a diamond’s crystal lattice that produce color — have received much attention for their sensitivity to magnetic fields. Researchers have now used N-V diamond sensors to detect the tiny magnetic fluctuations that occur on the surface of high-temperature superconductors in hopes of discovering how these much ballyhooed but still mysterious materials work. With their chip sensor, they hope to measure the properties of a single magnetic vortex.